TULSA, Oklahoma – A man charged in a deadly 2009 crash that killed three members of a Sand Springs family pleaded guilty Monday to three counts of first-degree manslaughter, the Tulsa County District Attorney's office said.

Steven Jameson, 21, also pleaded guilty to one count of possession of marijuana, the office said.

The crash happened on December 24, 2009, on state Highway 51 in Sand Springs just before the blizzard.

Prosecutors say Jameson was driving without a license when he crashed his Hummer head-on into a Chevy Cobalt. Michael Mulanax, 42; his wife Angela, 41, and their son James Mulanax, 18, were killed.

The Mulanax's 15-year-old daughter wasn't in the car.

"Our family has been devastated. There's nothing worse than losing a child, but when your entire family is wiped out its undescribable and overwhelming," Betty Carl said at the time of the accident.

Jameson reportedly told police he had looked at his dog in the back seat of the vehicle when he noticed he was driving into oncoming traffic.

Jameson's attorney says his client admitted to driving without a license at the time of the crash, but said drugs were not a factor. He said they have more than two dozen witnesses who say Jameson wasn't under the influence at the time of the deadly crash.

Prosecutors say they have a blood test proving Jameson had marijuana in his system.

Betty Carl said she worries people will think Jameson is just a young man who made a mistake. But she said he's made a series of them, pointing to his latest arrest in Stillwater just six months ago for marijuana possession.

Carl says she's afraid if Jameson doesn't get a stiff punishment, someone else could be robbed of their loved ones.Jameson's plea was not part of a deal with prosecutors, so the judge will decide the sentence. He faces a punishment of up to life in prison for each count of manslaughter and/or a $10,000 fine.

"I'm going to be doing everything I can to put together evidence that I can present to the judge at the time of sentencing for the judge so he can appreciate the gravity of this type of crime," Kunzweiler said.

Perkins said she was "caught off guard" by the plea. She says she was disappointed, not in the plea, but because she wasn't at the hearing Monday. She said she's been there for nearly all of the court proceedings because she promised her daughter at her grave that she would get justice "because [her daughter] didn't have to die."

"Someone has to be their voice," Perkins continued.

Perkins, who lives near Little Rock, Arkansas, said she "trusts the legal system will bring a fair and just conclusion."

Steven Jameson is being held without bond. He is scheduled to be sentenced on July 29, 2011.